A pedal powered bicycle having a pair of series chain driven transmissions, particularly, a peddle attached sprocket that drives the input of a first transmission through a single or multi speed sprocket assembly and a second transmission driven by the output of the first transmission. The output of the second transmission supplies rotational power to the rear bicycle wheel.
U.S. Pat. No. 1,360,032 issued to E. and J. Schiffner teaches a pedal driven dual series chain drive system. Gearing is achieved by the various sprocket diameters.
U.S. Pat. No. 1,535,714 issued to inventor Lot F. Burke teaches the use of a conventional pedal shaft attached sprocket and a pair of attached sprockets spaced therefrom. The pair of sprockets are driven by a chain between one of the sprockets and the pedal shaft sprocket. The second sprocket of the attached pair drives a rear wheel sprocket. Gearing is achieved by the size ratio of the various sprockets.
U.S. Pat. No. 3,921,467 issued to Hideji Matsuura teaches a chain drive for a bicycle that includes a secondary sprocket to alter the ratios of the drive train.
U.S. Pat. No. 4,826,191 issued to Daniel A. Matre and Jeffrey L. Bleustein teaches a velocipede such as a bicycle or tricycle that includes a drive sprocket mounted on a frame for adjustment between a plurality of positions defining an arcuate path having an axis of curvature. A second sprocket is rotatably mounted on the axis and is coupled to drive sprocket by a first chain. A third sprocket is mounted coaxially with and is coupled to the second sprocket for rotation therewith. A fourth sprocket is mounted on the rear wheel and coupled to the third sprocket by a second drive chain.
U.S. Pat. No. 5,102,155 issued to Ta-Chin Chou teaches a speed changing means mechanism imposed between a driving sprocket and a driven sprocket including a small intermediate sprocket mounted rotatably to the bicycle frame, a first chain entrained on the driving sprocket and the small intermediate sprocket, a large intermediate sprocket connected securely and coaxially to the small intermediate sprocket, a second chain entrained on the large intermediate socket. The sprockets have selected radii.
U.S. Pat. No. 5,873,590 issued to Minoru Abe et al. teaches a pair of transmissions operating in series between the driven sprocket of the pedal crank and the rear wheel of a bicycle.
This invention is directed to a bicycle that has elevated pedals that can be operable even in a tight turn without contacting the wheel support medium and a pair of series transmissions for driving the rear wheel by pedal rotation.
The bicycle has an elevated central frame relative to the wheels and support surface. By elevating the frame the pedals driving the bicycle are elevated above the bicycle support surface allowing pedaling through tight turns without fear of contacting the bicycle support surface. The pedal crank drives a first sprocket fixedly attached thereto that drives a second sprocket attached to the first transmission via an inter connecting chain. The second sprocket is fixedly attached to one end of a first shaft with the opposite end of the first shaft fixedly attached to a second shaft that is positioned normal to the centerline of the first shaft. The second shaft carries a pair of first gears rotatably positioned on each end thereof.
The first sprocket can be a single sprocket with a selected number of chain engaging teeth or can be a plurality of side by side of ganged together sprockets each of which has a different number of chain engaging teeth with means for selecting any one of the side by side sprockets. The ganged together sprocket assembly is conventional and well known for multiple gearing of bicycles.
A first transmission is driven by a first closed loop chain extending between the first sprocket and a second sprocket associated with the first transmission. The first transmission includes a first housing fixedly attached to the bicycle structure for non rotation, a first ring gear fixedly attached to the housing, a driven shaft driven by the first closed loop chain, a first shaft normal to the driven shaft and fixedly attached to the distal end thereof for rotation therewith, a pair of first pinon gears rotatably attached to the distal ends of the first, shaft. A second ring gear is rotated by the rotation of the pair of first pinion gears. The second ring gear is fixedly attached to an output shaft that drives a third sprocket. The second transmission is constructed and operates the same as the first transmission.
When peddling, the chain between the first sprocket and the second sprocket rotates the first pair of pinion gears which in turn rotate the second ring gear driving the output shaft in the same direction of rotation as the first input shaft at a multiple of the input speed, generally twice the speed, as desired. The output shaft of the first transmission is fixedly attached to a third sprocket that rotates therewith.
The third sprocket is attached through a second chain to a fourth sprocket that drives a second transmission. The second transmission is identical to the first transmission and operates in the same manner producing a output rotation greater than the input speed. Generally, as afore mentioned, twice the input speed is desirable. The output shaft of the second transmission drives the rear wheel of the bicycle at a multiple of the input speed with about four times the input speed of the first transmission being desirable.
The bicycle has a conventional fork assembly with a steerable front wheel rotatably attached thereto. The first and second transmissions and rear wheel are pivotally attached to the frame remote from the front wheel by a pivot pin positioned through apertures in the frame and rear wheels assembly. A shock absorber 30 of the hydraulic type or a spring or a combination of both is inter connected to the pivotal rear portion and the frame thereby providing shock dampening bias between the rear pivotal portion and the frame.
The bicycle generally resembles a conventional two wheeled bicycle.
The principal object of this invention is to provide a bicycle with elevated pedals that can be continually pedaled in a sharp banked turn.
Another object of the invention is to provide a fixed increased RPM in rear wheel speed relative to the pedal speed.
Still another object of the invention is to require less energy from the bicycle operator to achieve any desired speed on flat or inclined surfaces.
Other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, in which like reference numerals designate the same or similar parts throughout.